drivers/spi/spi_butterfly.c - kernel/msm - Gitiles

 /*
  * spi_butterfly.c - parport-to-butterfly adapter
  *
  * Copyright (C) 2005 David Brownell
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 #include <linux/config.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/parport.h>

 #include <linux/spi/spi.h>
 #include <linux/spi/spi_bitbang.h>
 #include <linux/spi/flash.h>

 #include <linux/mtd/partitions.h>


 /*
  * This uses SPI to talk with an "AVR Butterfly", which is a $US20 card
  * with a battery powered AVR microcontroller and lots of goodies.  You
  * can use GCC to develop firmware for this.
  *
  * See Documentation/spi/butterfly for information about how to build
  * and use this custom parallel port cable.
  */

 #undef	HAVE_USI	/* nyet */


 /* DATA output bits (pins 2..9 == D0..D7) */
 #define	butterfly_nreset (1 << 1)		/* pin 3 */

 #define	spi_sck_bit	(1 << 0)		/* pin 2 */
 #define	spi_mosi_bit	(1 << 7)		/* pin 9 */

 #define	usi_sck_bit	(1 << 3)		/* pin 5 */
 #define	usi_mosi_bit	(1 << 4)		/* pin 6 */

 #define	vcc_bits	((1 << 6) | (1 << 5))	/* pins 7, 8 */

 /* STATUS input bits */
 #define	spi_miso_bit	PARPORT_STATUS_BUSY	/* pin 11 */

 #define	usi_miso_bit	PARPORT_STATUS_PAPEROUT	/* pin 12 */

 /* CONTROL output bits */
 #define	spi_cs_bit	PARPORT_CONTROL_SELECT	/* pin 17 */
 /* USI uses no chipselect */


 static inline struct butterfly *spidev_to_pp(struct spi_device *spi)
 {
 	return spi->controller_data;
 }

 static inline int is_usidev(struct spi_device *spi)
 {
 #ifdef	HAVE_USI
 	return spi->chip_select != 1;
 #else
 	return 0;
 #endif
 }


 struct butterfly {
 	/* REVISIT ... for now, this must be first */
 	struct spi_bitbang	bitbang;

 	struct parport		*port;
 	struct pardevice	*pd;

 	u8			lastbyte;

 	struct spi_device	*dataflash;
 	struct spi_device	*butterfly;
 	struct spi_board_info	info[2];

 };

 /*----------------------------------------------------------------------*/

 /*
  * these routines may be slower than necessary because they're hiding
  * the fact that there are two different SPI busses on this cable: one
  * to the DataFlash chip (or AVR SPI controller), the other to the
  * AVR USI controller.
  */

 static inline void
 setsck(struct spi_device *spi, int is_on)
 {
 	struct butterfly	*pp = spidev_to_pp(spi);
 	u8			bit, byte = pp->lastbyte;

 	if (is_usidev(spi))
 		bit = usi_sck_bit;
 	else
 		bit = spi_sck_bit;

 	if (is_on)
 		byte |= bit;
 	else
 		byte &= ~bit;
 	parport_write_data(pp->port, byte);
 	pp->lastbyte = byte;
 }

 static inline void
 setmosi(struct spi_device *spi, int is_on)
 {
 	struct butterfly	*pp = spidev_to_pp(spi);
 	u8			bit, byte = pp->lastbyte;

 	if (is_usidev(spi))
 		bit = usi_mosi_bit;
 	else
 		bit = spi_mosi_bit;

 	if (is_on)
 		byte |= bit;
 	else
 		byte &= ~bit;
 	parport_write_data(pp->port, byte);
 	pp->lastbyte = byte;
 }

 static inline int getmiso(struct spi_device *spi)
 {
 	struct butterfly	*pp = spidev_to_pp(spi);
 	int			value;
 	u8			bit;

 	if (is_usidev(spi))
 		bit = usi_miso_bit;
 	else
 		bit = spi_miso_bit;

 	/* only STATUS_BUSY is NOT negated */
 	value = !(parport_read_status(pp->port) & bit);
 	return (bit == PARPORT_STATUS_BUSY) ? value : !value;
 }

 static void butterfly_chipselect(struct spi_device *spi, int value)
 {
 	struct butterfly	*pp = spidev_to_pp(spi);

 	/* set default clock polarity */
 	if (value != BITBANG_CS_INACTIVE)
 		setsck(spi, spi->mode & SPI_CPOL);

 	/* no chipselect on this USI link config */
 	if (is_usidev(spi))
 		return;

 	/* here, value == "activate or not";
 	 * most PARPORT_CONTROL_* bits are negated, so we must
 	 * morph it to value == "bit value to write in control register"
 	 */
 	if (spi_cs_bit == PARPORT_CONTROL_INIT)
 		value = !value;

 	parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0);
 }


 /* we only needed to implement one mode here, and choose SPI_MODE_0 */

 #define	spidelay(X)	do{}while(0)
 //#define	spidelay	ndelay

 #define	EXPAND_BITBANG_TXRX
 #include <linux/spi/spi_bitbang.h>

 static u32
 butterfly_txrx_word_mode0(struct spi_device *spi,
 		unsigned nsecs,
 		u32 word, u8 bits)
 {
 	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
 }

 /*----------------------------------------------------------------------*/

 /* override default partitioning with cmdlinepart */
 static struct mtd_partition partitions[] = { {
 	/* JFFS2 wants partitions of 4*N blocks for this device,
 	 * so sectors 0 and 1 can't be partitions by themselves.
 	 */

 	/* sector 0 = 8 pages * 264 bytes/page (1 block)
 	 * sector 1 = 248 pages * 264 bytes/page
 	 */
 	.name		= "bookkeeping",	// 66 KB
 	.offset		= 0,
 	.size		= (8 + 248) * 264,
 //	.mask_flags	= MTD_WRITEABLE,
 }, {
 	/* sector 2 = 256 pages * 264 bytes/page
 	 * sectors 3-5 = 512 pages * 264 bytes/page
 	 */
 	.name		= "filesystem",		// 462 KB
 	.offset		= MTDPART_OFS_APPEND,
 	.size		= MTDPART_SIZ_FULL,
 } };

 static struct flash_platform_data flash = {
 	.name		= "butterflash",
 	.parts		= partitions,
 	.nr_parts	= ARRAY_SIZE(partitions),
 };


 /* REVISIT remove this ugly global and its "only one" limitation */
 static struct butterfly *butterfly;

 static void butterfly_attach(struct parport *p)
 {
 	struct pardevice	*pd;
 	int			status;
 	struct butterfly	*pp;
 	struct spi_master	*master;
 	struct platform_device	*pdev;

 	if (butterfly)
 		return;

 	/* REVISIT:  this just _assumes_ a butterfly is there ... no probe,
 	 * and no way to be selective about what it binds to.
 	 */

 	/* FIXME where should master->cdev.dev come from?
 	 * e.g. /sys/bus/pnp0/00:0b, some PCI thing, etc
 	 * setting up a platform device like this is an ugly kluge...
 	 */
 	pdev = platform_device_register_simple("butterfly", -1, NULL, 0);

 	master = spi_alloc_master(&pdev->dev, sizeof *pp);
 	if (!master) {
 		status = -ENOMEM;
 		goto done;
 	}
 	pp = spi_master_get_devdata(master);

 	/*
 	 * SPI and bitbang hookup
 	 *
 	 * use default setup(), cleanup(), and transfer() methods; and
 	 * only bother implementing mode 0.  Start it later.
 	 */
 	master->bus_num = 42;
 	master->num_chipselect = 2;

 	pp->bitbang.master = spi_master_get(master);
 	pp->bitbang.chipselect = butterfly_chipselect;
 	pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0;

 	/*
 	 * parport hookup
 	 */
 	pp->port = p;
 	pd = parport_register_device(p, "spi_butterfly",
 			NULL, NULL, NULL,
 			0 /* FLAGS */, pp);
 	if (!pd) {
 		status = -ENOMEM;
 		goto clean0;
 	}
 	pp->pd = pd;

 	status = parport_claim(pd);
 	if (status < 0)
 		goto clean1;

 	/*
 	 * Butterfly reset, powerup, run firmware
 	 */
 	pr_debug("%s: powerup/reset Butterfly\n", p->name);

 	/* nCS for dataflash (this bit is inverted on output) */
 	parport_frob_control(pp->port, spi_cs_bit, 0);

 	/* stabilize power with chip in reset (nRESET), and
 	 * both spi_sck_bit and usi_sck_bit clear (CPOL=0)
 	 */
 	pp->lastbyte |= vcc_bits;
 	parport_write_data(pp->port, pp->lastbyte);
 	msleep(5);

 	/* take it out of reset; assume long reset delay */
 	pp->lastbyte |= butterfly_nreset;
 	parport_write_data(pp->port, pp->lastbyte);
 	msleep(100);


 	/*
 	 * Start SPI ... for now, hide that we're two physical busses.
 	 */
 	status = spi_bitbang_start(&pp->bitbang);
 	if (status < 0)
 		goto clean2;

 	/* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR
 	 * (firmware resets at45, acts as spi slave) or neither (we ignore
 	 * both, AVR uses AT45).  Here we expect firmware for the first option.
 	 */

 	pp->info[0].max_speed_hz = 15 * 1000 * 1000;
 	strcpy(pp->info[0].modalias, "mtd_dataflash");
 	pp->info[0].platform_data = &flash;
 	pp->info[0].chip_select = 1;
 	pp->info[0].controller_data = pp;
 	pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]);
 	if (pp->dataflash)
 		pr_debug("%s: dataflash at %s\n", p->name,
 				pp->dataflash->dev.bus_id);

 #ifdef	HAVE_USI
 	/* Bus 2 is only for talking to the AVR, and it can work no
 	 * matter who masters bus 1; needs appropriate AVR firmware.
 	 */
 	pp->info[1].max_speed_hz = 10 /* ?? */ * 1000 * 1000;
 	strcpy(pp->info[1].modalias, "butterfly");
 	// pp->info[1].platform_data = ... TBD ... ;
 	pp->info[1].chip_select = 2,
 	pp->info[1].controller_data = pp;
 	pp->butterfly = spi_new_device(pp->bitbang.master, &pp->info[1]);
 	if (pp->butterfly)
 		pr_debug("%s: butterfly at %s\n", p->name,
 				pp->butterfly->dev.bus_id);

 	/* FIXME setup ACK for the IRQ line ...  */
 #endif

 	// dev_info(_what?_, ...)
 	pr_info("%s: AVR Butterfly\n", p->name);
 	butterfly = pp;
 	return;

 clean2:
 	/* turn off VCC */
 	parport_write_data(pp->port, 0);

 	parport_release(pp->pd);
 clean1:
 	parport_unregister_device(pd);
 clean0:
 	(void) spi_master_put(pp->bitbang.master);
 done:
 	platform_device_unregister(pdev);
 	pr_debug("%s: butterfly probe, fail %d\n", p->name, status);
 }

 static void butterfly_detach(struct parport *p)
 {
 	struct butterfly	*pp;
 	struct platform_device	*pdev;
 	int			status;

 	/* FIXME this global is ugly ... but, how to quickly get from
 	 * the parport to the "struct butterfly" associated with it?
 	 * "old school" driver-internal device lists?
 	 */
 	if (!butterfly || butterfly->port != p)
 		return;
 	pp = butterfly;
 	butterfly = NULL;

 	/* stop() unregisters child devices too */
 	pdev = to_platform_device(pp->bitbang.master->cdev.dev);
 	status = spi_bitbang_stop(&pp->bitbang);

 	/* turn off VCC */
 	parport_write_data(pp->port, 0);
 	msleep(10);

 	parport_release(pp->pd);
 	parport_unregister_device(pp->pd);

 	(void) spi_master_put(pp->bitbang.master);

 	platform_device_unregister(pdev);
 }

 static struct parport_driver butterfly_driver = {
 	.name =		"spi_butterfly",
 	.attach =	butterfly_attach,
 	.detach =	butterfly_detach,
 };


 static int __init butterfly_init(void)
 {
 	return parport_register_driver(&butterfly_driver);
 }
 device_initcall(butterfly_init);

 static void __exit butterfly_exit(void)
 {
 	parport_unregister_driver(&butterfly_driver);
 }
 module_exit(butterfly_exit);

 MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly");
 MODULE_LICENSE("GPL");
	/*
	* spi_butterfly.c - parport-to-butterfly adapter
	*
	* Copyright (C) 2005 David Brownell
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/
	#include <linux/config.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/delay.h>
	#include <linux/platform_device.h>
	#include <linux/parport.h>

	#include <linux/spi/spi.h>
	#include <linux/spi/spi_bitbang.h>
	#include <linux/spi/flash.h>

	#include <linux/mtd/partitions.h>


	/*
	* This uses SPI to talk with an "AVR Butterfly", which is a $US20 card
	* with a battery powered AVR microcontroller and lots of goodies. You
	* can use GCC to develop firmware for this.
	*
	* See Documentation/spi/butterfly for information about how to build
	* and use this custom parallel port cable.
	*/

	#undef HAVE_USI /* nyet */


	/* DATA output bits (pins 2..9 == D0..D7) */
	#define butterfly_nreset (1 << 1) /* pin 3 */

	#define spi_sck_bit (1 << 0) /* pin 2 */
	#define spi_mosi_bit (1 << 7) /* pin 9 */

	#define usi_sck_bit (1 << 3) /* pin 5 */
	#define usi_mosi_bit (1 << 4) /* pin 6 */

	#define vcc_bits ((1 << 6) \| (1 << 5)) /* pins 7, 8 */

	/* STATUS input bits */
	#define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */

	#define usi_miso_bit PARPORT_STATUS_PAPEROUT /* pin 12 */

	/* CONTROL output bits */
	#define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */
	/* USI uses no chipselect */



	static inline struct butterfly spidev_to_pp(struct spi_device spi)
	{
	return spi->controller_data;
	}

	static inline int is_usidev(struct spi_device *spi)
	{
	#ifdef HAVE_USI
	return spi->chip_select != 1;
	#else
	return 0;
	#endif
	}


	struct butterfly {
	/* REVISIT ... for now, this must be first */
	struct spi_bitbang bitbang;

	struct parport *port;
	struct pardevice *pd;

	u8 lastbyte;

	struct spi_device *dataflash;
	struct spi_device *butterfly;
	struct spi_board_info info[2];

	};

	/----------------------------------------------------------------------/

	/*
	* these routines may be slower than necessary because they're hiding
	* the fact that there are two different SPI busses on this cable: one
	* to the DataFlash chip (or AVR SPI controller), the other to the
	* AVR USI controller.
	*/

	static inline void
	setsck(struct spi_device *spi, int is_on)
	{
	struct butterfly *pp = spidev_to_pp(spi);
	u8 bit, byte = pp->lastbyte;

	if (is_usidev(spi))
	bit = usi_sck_bit;
	else
	bit = spi_sck_bit;

	if (is_on)
	byte \|= bit;
	else
	byte &= ~bit;
	parport_write_data(pp->port, byte);
	pp->lastbyte = byte;
	}

	static inline void
	setmosi(struct spi_device *spi, int is_on)
	{
	struct butterfly *pp = spidev_to_pp(spi);
	u8 bit, byte = pp->lastbyte;

	if (is_usidev(spi))
	bit = usi_mosi_bit;
	else
	bit = spi_mosi_bit;

	if (is_on)
	byte \|= bit;
	else
	byte &= ~bit;
	parport_write_data(pp->port, byte);
	pp->lastbyte = byte;
	}

	static inline int getmiso(struct spi_device *spi)
	{
	struct butterfly *pp = spidev_to_pp(spi);
	int value;
	u8 bit;

	if (is_usidev(spi))
	bit = usi_miso_bit;
	else
	bit = spi_miso_bit;

	/* only STATUS_BUSY is NOT negated */
	value = !(parport_read_status(pp->port) & bit);
	return (bit == PARPORT_STATUS_BUSY) ? value : !value;
	}

	static void butterfly_chipselect(struct spi_device *spi, int value)
	{
	struct butterfly *pp = spidev_to_pp(spi);

	/* set default clock polarity */
	if (value != BITBANG_CS_INACTIVE)
	setsck(spi, spi->mode & SPI_CPOL);

	/* no chipselect on this USI link config */
	if (is_usidev(spi))
	return;

	/* here, value == "activate or not";
	* most PARPORT_CONTROL_* bits are negated, so we must
	* morph it to value == "bit value to write in control register"
	*/
	if (spi_cs_bit == PARPORT_CONTROL_INIT)
	value = !value;

	parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0);
	}


	/* we only needed to implement one mode here, and choose SPI_MODE_0 */

	#define spidelay(X) do{}while(0)
	//#define spidelay ndelay

	#define EXPAND_BITBANG_TXRX
	#include <linux/spi/spi_bitbang.h>

	static u32
	butterfly_txrx_word_mode0(struct spi_device *spi,
	unsigned nsecs,
	u32 word, u8 bits)
	{
	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
	}

	/----------------------------------------------------------------------/

	/* override default partitioning with cmdlinepart */
	static struct mtd_partition partitions[] = { {
	/* JFFS2 wants partitions of 4*N blocks for this device,
	* so sectors 0 and 1 can't be partitions by themselves.
	*/

	/* sector 0 = 8 pages * 264 bytes/page (1 block)
	* sector 1 = 248 pages * 264 bytes/page
	*/
	.name = "bookkeeping", // 66 KB
	.offset = 0,
	.size = (8 + 248) * 264,
	// .mask_flags = MTD_WRITEABLE,
	}, {
	/* sector 2 = 256 pages * 264 bytes/page
	* sectors 3-5 = 512 pages * 264 bytes/page
	*/
	.name = "filesystem", // 462 KB
	.offset = MTDPART_OFS_APPEND,
	.size = MTDPART_SIZ_FULL,
	} };

	static struct flash_platform_data flash = {
	.name = "butterflash",
	.parts = partitions,
	.nr_parts = ARRAY_SIZE(partitions),
	};


	/* REVISIT remove this ugly global and its "only one" limitation */
	static struct butterfly *butterfly;

	static void butterfly_attach(struct parport *p)
	{
	struct pardevice *pd;
	int status;
	struct butterfly *pp;
	struct spi_master *master;
	struct platform_device *pdev;

	if (butterfly)
	return;

	/* REVISIT: this just _assumes_ a butterfly is there ... no probe,
	* and no way to be selective about what it binds to.
	*/

	/* FIXME where should master->cdev.dev come from?
	* e.g. /sys/bus/pnp0/00:0b, some PCI thing, etc
	* setting up a platform device like this is an ugly kluge...
	*/
	pdev = platform_device_register_simple("butterfly", -1, NULL, 0);

	master = spi_alloc_master(&pdev->dev, sizeof *pp);
	if (!master) {
	status = -ENOMEM;
	goto done;
	}
	pp = spi_master_get_devdata(master);

	/*
	* SPI and bitbang hookup
	*
	* use default setup(), cleanup(), and transfer() methods; and
	* only bother implementing mode 0. Start it later.
	*/
	master->bus_num = 42;
	master->num_chipselect = 2;

	pp->bitbang.master = spi_master_get(master);
	pp->bitbang.chipselect = butterfly_chipselect;
	pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0;

	/*
	* parport hookup
	*/
	pp->port = p;
	pd = parport_register_device(p, "spi_butterfly",
	NULL, NULL, NULL,
	0 /* FLAGS */, pp);
	if (!pd) {
	status = -ENOMEM;
	goto clean0;
	}
	pp->pd = pd;

	status = parport_claim(pd);
	if (status < 0)
	goto clean1;

	/*
	* Butterfly reset, powerup, run firmware
	*/
	pr_debug("%s: powerup/reset Butterfly\n", p->name);

	/* nCS for dataflash (this bit is inverted on output) */
	parport_frob_control(pp->port, spi_cs_bit, 0);

	/* stabilize power with chip in reset (nRESET), and
	* both spi_sck_bit and usi_sck_bit clear (CPOL=0)
	*/
	pp->lastbyte \|= vcc_bits;
	parport_write_data(pp->port, pp->lastbyte);
	msleep(5);

	/* take it out of reset; assume long reset delay */
	pp->lastbyte \|= butterfly_nreset;
	parport_write_data(pp->port, pp->lastbyte);
	msleep(100);


	/*
	* Start SPI ... for now, hide that we're two physical busses.
	*/
	status = spi_bitbang_start(&pp->bitbang);
	if (status < 0)
	goto clean2;

	/* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR
	* (firmware resets at45, acts as spi slave) or neither (we ignore
	* both, AVR uses AT45). Here we expect firmware for the first option.
	*/

	pp->info[0].max_speed_hz = 15 * 1000 * 1000;
	strcpy(pp->info[0].modalias, "mtd_dataflash");
	pp->info[0].platform_data = &flash;
	pp->info[0].chip_select = 1;
	pp->info[0].controller_data = pp;
	pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]);
	if (pp->dataflash)
	pr_debug("%s: dataflash at %s\n", p->name,
	pp->dataflash->dev.bus_id);

	#ifdef HAVE_USI
	/* Bus 2 is only for talking to the AVR, and it can work no
	* matter who masters bus 1; needs appropriate AVR firmware.
	*/
	pp->info[1].max_speed_hz = 10 /* ?? / 1000 * 1000;
	strcpy(pp->info[1].modalias, "butterfly");
	// pp->info[1].platform_data = ... TBD ... ;
	pp->info[1].chip_select = 2,
	pp->info[1].controller_data = pp;
	pp->butterfly = spi_new_device(pp->bitbang.master, &pp->info[1]);
	if (pp->butterfly)
	pr_debug("%s: butterfly at %s\n", p->name,
	pp->butterfly->dev.bus_id);

	/* FIXME setup ACK for the IRQ line ... */
	#endif

	// dev_info(_what?_, ...)
	pr_info("%s: AVR Butterfly\n", p->name);
	butterfly = pp;
	return;

	clean2:
	/* turn off VCC */
	parport_write_data(pp->port, 0);

	parport_release(pp->pd);
	clean1:
	parport_unregister_device(pd);
	clean0:
	(void) spi_master_put(pp->bitbang.master);
	done:
	platform_device_unregister(pdev);
	pr_debug("%s: butterfly probe, fail %d\n", p->name, status);
	}

	static void butterfly_detach(struct parport *p)
	{
	struct butterfly *pp;
	struct platform_device *pdev;
	int status;

	/* FIXME this global is ugly ... but, how to quickly get from
	* the parport to the "struct butterfly" associated with it?
	* "old school" driver-internal device lists?
	*/
	if (!butterfly \|\| butterfly->port != p)
	return;
	pp = butterfly;
	butterfly = NULL;

	/* stop() unregisters child devices too */
	pdev = to_platform_device(pp->bitbang.master->cdev.dev);
	status = spi_bitbang_stop(&pp->bitbang);

	/* turn off VCC */
	parport_write_data(pp->port, 0);
	msleep(10);

	parport_release(pp->pd);
	parport_unregister_device(pp->pd);

	(void) spi_master_put(pp->bitbang.master);

	platform_device_unregister(pdev);
	}

	static struct parport_driver butterfly_driver = {
	.name = "spi_butterfly",
	.attach = butterfly_attach,
	.detach = butterfly_detach,
	};


	static int __init butterfly_init(void)
	{
	return parport_register_driver(&butterfly_driver);
	}
	device_initcall(butterfly_init);

	static void __exit butterfly_exit(void)
	{
	parport_unregister_driver(&butterfly_driver);
	}
	module_exit(butterfly_exit);

	MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly");
	MODULE_LICENSE("GPL");